Use unit fractions to name and count fractional amounts
Using unit fractions (e.g. , one one-seventh, two one-sevenths, etc.) when counting fractional amounts, such as regions in a rectangle, rather than using a whole number count (e.g., 1, 2 ,3 ...), reinforces the meaning of the fraction.
A unit fraction is the base unit of any fraction and always has a numerator of 1; for example, 1⁄4, 1⁄15, 1⁄23 are all unit fractions. Every fraction can be decomposed into unit fractions. For example, 3⁄4 is 3 one-fourth units (so one-fourth is the unit fraction and we are thinking about 3 of them). Partitioning a model involves determining and creating a unit fraction.
Consider the fraction one and three-fourths. This number can be decomposed using a unit fraction.
One and two-fourths can be composed using a unit fraction.